Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts, USA.
Harvard Medical School, Boston, Massachusetts, USA.
Am J Sports Med. 2021 Jan;49(1):226-235. doi: 10.1177/0363546520971782. Epub 2020 Dec 1.
Bone stress injuries (BSIs) occur in up to 20% of runners and military personnel. Typically, after a period of unloading and gradual return to weightbearing activities, athletes return to unrestricted sports participation or military duty approximately 4 to 14 weeks after a BSI diagnosis, depending on the injury location and severity. However, the time course of the recovery of the bone's mechanical competence is not well-characterized, and reinjury rates are high.
To assess the bone microarchitecture and volumetric bone mineral density (vBMD) over 12 months after a tibial BSI diagnosis.
Case-control study; Level of evidence, 3.
We enrolled 30 female athletes from the local community (aged 18-35 years) with a tibial BSI (grade ≥2 of 4 on magnetic resonance imaging) for this prospective observational study. Participants completed a baseline visit within 3 weeks of the diagnosis. At baseline and 6, 12, 24, and 52 weeks after the BSI diagnosis, we collected high-resolution peripheral quantitative computed tomography scans of the ultradistal tibia (4% of tibial length) of the injured and uninjured legs as well as pain and physical activity assessment findings.
From baseline to 12 weeks after the diagnosis, total, trabecular, and cortical vBMD declined by 0.58% to 0.94% ( < .05 for all) in the injured leg. Total and trabecular vBMD also declined by 0.61% and 0.67%, respectively, in the uninjured leg ( < .05 for both). At 24 weeks, mean values for all bone parameters were nearly equivalent to baseline values, and by 52 weeks, several mean values had surpassed baseline values. Of the 30 participants, 10 incurred a subsequent BSI during the course of the study, and 1 of these 10 incurred 2 subsequent BSIs. Participants who suffered an additional BSI were younger and had a later age of menarche, a greater incidence of previous fractures, and lower serum parathyroid hormone levels ( < .05 for all).
Bone density declined in both the injured and the uninjured legs and, on average, did not return to baseline for 3 to 6 months after a tibial BSI diagnosis. The observed time to the recovery of baseline vBMD, coupled with the high rate of recurrent BSIs, suggests that improved return-to-sports and military duty guidelines may be in order.
骨骼应力性损伤（BSI）在高达 20%的跑步者和军人中发生。通常情况下，在经过一段时间的卸载和逐渐恢复负重活动后，运动员在 BSI 诊断后大约 4 至 14 周后恢复无限制的运动参与或军事任务，具体取决于损伤部位和严重程度。然而，骨骼机械能力恢复的时间过程尚未得到很好的描述，且再损伤率较高。
在胫骨 BSI 诊断后 12 个月评估骨微结构和体积骨密度（vBMD）。
病例对照研究；证据水平，3 级。
我们招募了 30 名来自当地社区的女性运动员（年龄 18-35 岁），患有胫骨 BSI（磁共振成像上为 4 级中的 2 级及以上），进行了这项前瞻性观察研究。参与者在诊断后 3 周内完成基线访视。在 BSI 诊断后 6、12、24 和 52 周时，我们采集了受伤和未受伤腿的超远端胫骨（胫骨长度的 4%）的高分辨率外周定量计算机断层扫描（pQCT）扫描，以及疼痛和身体活动评估结果。
从基线到诊断后 12 周，受伤腿的总、小梁和皮质 vBMD 分别下降了 0.58%至 0.94%（所有均<.05）。未受伤腿的总 vBMD 和小梁 vBMD 也分别下降了 0.61%和 0.67%（均<.05）。在 24 周时，所有骨参数的平均值几乎与基线值相等，而在 52 周时，几个平均值已经超过了基线值。在 30 名参与者中，有 10 名在研究过程中发生了后续 BSI，其中 1 名发生了 2 次后续 BSI。发生额外 BSI 的参与者更年轻，且月经初潮年龄较晚、既往骨折发生率更高、血清甲状旁腺激素水平更低（所有均<.05）。
受伤和未受伤腿的骨密度均下降，且平均而言，在胫骨 BSI 诊断后 3 至 6 个月内未恢复到基线水平。观察到恢复基线 vBMD 的时间，加上高复发 BSI 率，表明可能需要改进重返运动和军事任务的指南。
